The provision of toys to pigs can improve the human-animal relationship

Abstract

It is now widely recognised that a positive human-animal relationship is beneficial not only for farm animals’ welfare but also for productivity and the quality of products. A better understanding of animal emotions is an important goal in disciplines ranging from neuroscience to animal welfare science, but few reliable tools exist for measuring these emotions. In this study, whether the provision of toys to solicit play behaviour in pigs is associated with a change in the human-animal relationship and the emotional state of pigs was investigated. We involved a group of sixteen mini-pigs housed in an experimental setting and the use of a preliminary test called the ‘strange person’ test. After a Control and a Play session (with medium-sized dog toys, balls with ropes), the strange person test was performed. During the test, a person wearing a colourful overall, a hood, a mask, gloves and boots (unknown person with an odd appearance) entered the pen, where 2 mini-pigs were housed, for a 2-min video recording. The strange person test results after the Play and Control sessions were compared. The results showed that the latency to approach the person (duration in seconds) and the duration for which the pig was distant from the strange person (duration in seconds) were significantly lower after the Play session than after the Control session (Degrees of Freedom =30; Statistic of the F test =39.1; p < 0.0001 and Degrees of Freedom =15; Statistic of the F test =54.3; p < 0.0001, respectively). The duration of direct contact (duration in seconds) (Degrees of Freedom =15; Statistic of the F test =14.8; p = 0.002), the need to separate the pig from the strange person (frequency) (Degrees of Freedom =30; Statistic of the F test =9.3; p = 0.005) and the duration of tail movement (duration in seconds) (Degrees of Freedom =15; Statistic of the F test =12.6; p = 0.003) were all significantly higher after the Play sessions than after the Control sessions. Overall, the results suggest a change in the human-animal relationship after the Play sessions: the pigs seemed to be less fearful and more inclined to interact with the strange person, showing a more positive emotional state. This preliminary study suggests that the provision of toys, and more precisely, the opportunity to perform object play behaviour, and sometimes, spontaneously, social play behaviour, can improve the human-animal relationship. Additional research to explore this topic thoroughly may yield interesting results because a positive emotional state of the animals and a good human-animal relationship are essential to ensure good quality of life of farm animals.

The effects of age, size, and cage complexity on the behaviour of farmed female chinchillas (Chinchilla lanigera)

“…On the other hand, these observations are consistent with those carried out on many other species of farm, laboratory, and zoo animals, e.g. minks 36 , polar foxes 37 , pigs 38 , rats, and mice 39 , as well as non-human primates 40 . For example, enriching the cage environment by adding toys (gnawing objects) caused a significant changing of minks’ personalities, as estimated by empathic tests of the movement from “fearful” towards “confident”, while such a reaction was not observed in “aggressive” ones 12 .…”

Effects of reduced kinematic and social play experience on affective appraisal of human-rat play in rats

“…Reduced locomotor play leads to decreased locomotor function and/or physicality in several species [ 5 , 18 , 19 ]. The experience of object play has been associated with differences in cognition [ 20 , 21 ], and social play experience often has effects on social competence [ 22 – 24 ]. As useful as the traditional classification of play is, it still overlooks one crucial fact: the observed developmental effects of play are caused by play aspects that may overlap among play types.…”

Emotional “Contagion” in Piglets after Sensory Avoidance of Rewarding and Punishing Treatment

“…Studies have demonstrated that pigs are sensitive to the emotional states of group members, and pigs not directly stimulated can experience emotional states induced by exposure to the emotional responses of their peers which have undergone painful experiences [21]. Following exposure to negative stimuli and restraint treatments, both of the treated pigs and their untreated companions show negative emotional states, despite the companions not experiencing the treatment directly [21][22][23]. Emotional contagion among domestic animals could significantly affect herds' welfare.…”

“…Rewards and punishments are central to the elicitation of all emotional states; they determine the valence of emotions [24]. Both food rewards (such as syrup, apples, raisins, and chocolate) and punishment stimuli (including restraints, sudden noises, and thermal stimuli) are effective in inducing emotional states that persist after the stimulus [9,22]. Evidence of emotional contagion needs observers and demonstrators to have the same emotional valence, which provides ideas for this experimental design.…”